Deploying a Spring Boot Microservice on Kubernetes: Step-by-Step Guide

In this blog post, we'll walk through deploying a Spring Boot microservice on Kubernetes (K8s) using the provided Kubernetes manifest files. These files define a Deployment and a Service, ensuring that our microservice runs smoothly within the cluster. 1. Understanding the Manifest Files The provided YAML files define: A Deployment that manages the lifecycle of the microservice. A Service that exposes the microservice to the network. Let's go through the deployment process step by step. 2. Setting Up the Kubernetes Cluster Before deploying, ensure that you have a Kubernetes cluster running. You can use: Minikube (for local development) Docker Desktop Kubernetes A managed Kubernetes service (like AWS EKS, Azure AKS, or Google GKE) Check your Kubernetes setup with: kubectl cluster-info If you don't have Kubernetes installed, follow this guide to set it up. 3. Creating the Deployment Deployment YAML Explanation 1️⃣ Metadata Section apiVersion: apps/v1 kind: Deployment metadata: name: accounts-deployment labels: app: accounts Defines a Deployment named accounts-deployment. Uses labels (app: accounts) to identify the microservice. 2️⃣ Spec Section spec: replicas: 1 selector: matchLabels: app: accounts Creates one replica (you can increase this for scalability). Selects Pods using the matchLabels condition. 3️⃣ Pod Template (Under template: Section) template: metadata: labels: app: accounts Specifies the labels inside the Pod template. 4️⃣ Container Definition spec: containers: - name: accounts image: eazybytes/accounts:s12 ports: - containerPort: 8080 Defines a container named accounts. Uses the Docker image eazybytes/accounts:s12. Exposes port 8080 for incoming traffic. 5️⃣ Environment Variables (From ConfigMap) env: - name: SPRING_APPLICATION_NAME valueFrom: configMapKeyRef: name: eazybank-configmap key: ACCOUNTS_APPLICATION_NAME - name: SPRING_PROFILES_ACTIVE valueFrom: configMapKeyRef: name: eazybank-configmap key: SPRING_PROFILES_ACTIVE - name: SPRING_CONFIG_IMPORT valueFrom: configMapKeyRef: name: eazybank-configmap key: SPRING_CONFIG_IMPORT - name: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE valueFrom: configMapKeyRef: name: eazybank-configmap key: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE Pulls environment variables from a ConfigMap (eazybank-configmap). These variables configure Spring Boot profiles, Eureka client URL, and application name dynamically. Deploying the Application Run the following command to create the Deployment: kubectl apply -f deployment.yaml Verify the deployment: kubectl get deployments kubectl get pods If the Pod is running, you should see an output similar to: NAME READY STATUS RESTARTS AGE accounts-deployment 1/1 Running 0 10s 4. Exposing the Service Service YAML Explanation apiVersion: v1 kind: Service metadata: name: accounts spec: selector: app: accounts type: LoadBalancer ports: - protocol: TCP port: 8080 targetPort: 8080 Creates a Service named accounts. Selects Pods with the label app: accounts. Uses LoadBalancer to expose the service externally. Maps port 8080 on the Service to port 8080 in the container. Deploying the Service Run the following command: kubectl apply -f service.yaml Check the service: kubectl get services If successful, you'll see an output like: NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE accounts LoadBalancer 10.100.200.100 8080:30000/TCP 10s If you're running Minikube, use minikube service accounts --url to get the external URL. 5. Accessing the Application Once the LoadBalancer is ready, you can access the service using: http://:8080 For Minikube users, use: minikube service accounts --url To check logs from the running Pod: kubectl logs -f 6. Scaling the Application You can scale the Deployment to handle more traffic: kubectl scale deployment accounts-deployment --replicas=3 Verify the new replica count: kubectl get pods 7. Cleaning Up To delete the deployment and service: kubectl delete -f deployment.yaml kubectl delete -f service.yaml Conclusion In this guide, we: ✅ Created a Deployment for a Spring Boot microservice. ✅ Defined a Service to expose the microservice. ✅ Used a Confi

Feb 22, 2025 - 07:41

Deploying a Spring Boot Microservice on Kubernetes: Step-by-Step Guide

In this blog post, we'll walk through deploying a Spring Boot microservice on Kubernetes (K8s) using the provided Kubernetes manifest files. These files define a Deployment and a Service, ensuring that our microservice runs smoothly within the cluster.

1. Understanding the Manifest Files

The provided YAML files define:

A Deployment that manages the lifecycle of the microservice.
A Service that exposes the microservice to the network.

Let's go through the deployment process step by step.

2. Setting Up the Kubernetes Cluster

Before deploying, ensure that you have a Kubernetes cluster running. You can use:

Minikube (for local development)
Docker Desktop Kubernetes
A managed Kubernetes service (like AWS EKS, Azure AKS, or Google GKE)

Check your Kubernetes setup with:

kubectl cluster-info

If you don't have Kubernetes installed, follow this guide to set it up.

3. Creating the Deployment

Deployment YAML Explanation

1️⃣ Metadata Section

apiVersion: apps/v1
kind: Deployment
metadata:
  name: accounts-deployment
  labels:
    app: accounts

Defines a Deployment named accounts-deployment.
Uses labels (app: accounts) to identify the microservice.

2️⃣ Spec Section

spec:
  replicas: 1
  selector:
    matchLabels:
      app: accounts

Creates one replica (you can increase this for scalability).
Selects Pods using the matchLabels condition.

3️⃣ Pod Template (Under `template:` Section)

    template:
      metadata:
        labels:
          app: accounts

Specifies the labels inside the Pod template.

4️⃣ Container Definition

    spec:
      containers:
      - name: accounts
        image: eazybytes/accounts:s12
        ports:
        - containerPort: 8080

Defines a container named accounts.
Uses the Docker image eazybytes/accounts:s12.
Exposes port 8080 for incoming traffic.

5️⃣ Environment Variables (From ConfigMap)

        env:
        - name: SPRING_APPLICATION_NAME
          valueFrom:
            configMapKeyRef:
              name: eazybank-configmap
              key: ACCOUNTS_APPLICATION_NAME
        - name: SPRING_PROFILES_ACTIVE
          valueFrom: 
            configMapKeyRef:
              name: eazybank-configmap
              key: SPRING_PROFILES_ACTIVE
        - name: SPRING_CONFIG_IMPORT
          valueFrom: 
            configMapKeyRef:
              name: eazybank-configmap
              key: SPRING_CONFIG_IMPORT
        - name: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE
          valueFrom: 
            configMapKeyRef:
              name: eazybank-configmap
              key: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE

Pulls environment variables from a ConfigMap (eazybank-configmap).
These variables configure Spring Boot profiles, Eureka client URL, and application name dynamically.

Deploying the Application

Run the following command to create the Deployment:

kubectl apply -f deployment.yaml

Verify the deployment:

kubectl get deployments
kubectl get pods

If the Pod is running, you should see an output similar to:

NAME                   READY   STATUS    RESTARTS   AGE
accounts-deployment    1/1     Running   0          10s

4. Exposing the Service

Service YAML Explanation

apiVersion: v1
kind: Service
metadata:
  name: accounts
spec:
  selector:
    app: accounts
  type: LoadBalancer
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8080

Creates a Service named accounts.
Selects Pods with the label app: accounts.
Uses LoadBalancer to expose the service externally.
Maps port 8080 on the Service to port 8080 in the container.

Deploying the Service

Run the following command:

kubectl apply -f service.yaml

Check the service:

kubectl get services

If successful, you'll see an output like:

NAME       TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
accounts   LoadBalancer   10.100.200.100        8080:30000/TCP   10s

If you're running Minikube, use minikube service accounts --url to get the external URL.

5. Accessing the Application

Once the LoadBalancer is ready, you can access the service using:

http://:8080

For Minikube users, use:

minikube service accounts --url

To check logs from the running Pod:

kubectl logs -f

6. Scaling the Application

You can scale the Deployment to handle more traffic:

kubectl scale deployment accounts-deployment --replicas=3

Verify the new replica count:

kubectl get pods

7. Cleaning Up

To delete the deployment and service:

kubectl delete -f deployment.yaml
kubectl delete -f service.yaml

Conclusion

In this guide, we:

✅ Created a Deployment for a Spring Boot microservice.

✅ Defined a Service to expose the microservice.

✅ Used a ConfigMap to manage environment variables.

✅ Scaled the application dynamically.

Now your microservice is running on Kubernetes!